// index.js

window.onload = function () {

	// 初始化网页头部
	initHeader();

}

function initHeader() {
	var headerEl = document.getElementById("J-header");
	window.onscroll = function() {
		var scrollTop = document.documentElement.scrollTop
		if (scrollTop >= 40) {
			headerEl.className = "header";
		} else {
			headerEl.className = ".header .navi-bottom";
		}
	}
}